(1.0) Field of the Invention
The present invention relates to a modular launcher for launching missiles, torpedoes, sensors, or counter measures and, more particularly, to a modular launcher that reduces the reinforcement needs of a ship carrying the modular launcher while at the same time reduces the adverse affects commonly caused by the shock of the device being launched.
(2.0) Description of the Related Art
The primary types of missile launching systems consist of systems that are deck mounted and ones that are enclosed by the vessel, such as built-in launchers enclosed by the hull of the ship. The deck mounted launchers either stow the weapons ready to fire in the launcher, or stow the weapons in magazines below or beside the launcher. If the weapons are not stowed ready to fire, machinery is used to load the missiles into the launcher prior to use or to reload after firing. One such launching system fires the weapons from the magazine from within the ship. When the weapons are fired from within the ship, the exhaust gas from the rocket motor has to be conveyed out of the launcher space and discharged into the atmosphere. Exhaust gas management is an important aspect of designing this type of missile launcher. In one such launching system, the exhaust is captured in a plenum chamber under the missiles and then vented out of the plenum through an uptake (chimney). The uptake runs the width of the launcher and a large free area is required to avoid excessive pressure in the plenum and the uptake. Concentric canister launchers, such as those disclosed in U.S. patent application Ser. No. 08/772,054, now U.S. Pat. No. 5,837,919 and its continuation-in-part application U.S. patent application Ser. No. 09/070,770 and both of which are herein incorporated by reference, pass exhaust gas through an annular space between the cylinders and avoids excessive pressure in the plenum of the launching system.
For existing launching systems foundations are provided in the ship. In one such system, and for rotating arm launchers that load missiles from a magazine space below deck, a relatively large foundation needs to be provided and is located relatively low in the ship. One of the design requirements for launching systems is shock resistance and which has been a difficult design problem for all types of missile launching equipment. Relatively large missile launchers, with equipment foundations very low in the ship, have been especially difficult to design. This is because the shock motions created by underwater explosions are most severe in the keel of the ship. As one moves up and away from the keel, the elastic path associated with shock resistance becomes longer, and the shock advantageously becomes less intense.
With all types of weapons installations that penetrate the deck of a ship, great care has to be taken in the design parameters associated with the penetration. Although designing a penetration has to be one of the oldest problems in naval architecture and marine engineering, it still remains a relatively unsolved problem, especially for launching systems. Penetration parameters associated with warship hull-girder design uses the deck of the ship as a primary structural element that is to be penetrated and beam theory is used to design the deck of the ship. The deck of the ship is analogous to flange of an I-beam. When one penetrates or removes a portion of the deck to allow installation of a weapon, such as a launcher system, the bending strength of the deck is greatly compromised. Considerable reinforcement of the deck is required to recover the lost section modulus caused by the penetration. The larger the opening caused by the penetration, the more severe the requirement for reinforcement of the opening becomes, and the more difficult it becomes to maintain the flexural and torsional rigidity of the ship. Stress concentrations around the openings create additional challenges. For example, the mathematical theory of elasticity show that the stress concentration factor around a circular hole in a plate, such as that used for the deck of a ship, is three, i.e., the stress at the hole is three times the stress away from the hole. The size of the hole does not matter, but the shape has an impact. A square hole is much worse than a round hole. The perfectly square hole has theoretical stress concentration of infinity. Therefore, the openings that are basically rectangular, must use radiused corners to reduce stress concentration. Thus, the design problem associated with deck penetrations is two-fold, one must provide sufficient reinforcement to recover the lost section, and then the design must be further refined and detailed to minimize the stress concentrations. When all this is done considerable additional structural mass making up the reinforcements associated with deck penetrations results. When added to the weight of the weapon, there is a concentrated load in this part of the ship having the penetrated deck caused by the added launcher, which requires additional design effort, especially when shock loads drive the design process. It is desired to provide a solution that eliminates the bulky reinforcements of conventional penetrations into the deck of a ship, and to reduce stress concentration and foundation motions, both created by the launching of devices from a launching system.